This invention relates generally to equipment for treating laundry which uses a rotatable spin-drying perforated drum disposed within a housing. The invention more particularly pertains to equipment utilized for the extraction, or more accurately, the pre-extraction, of water by centrifugal force, from previously washed laundry which is placed in condition for such treatment by drying or wringing steps which precede the extraction action.
Throughout the specification "treatment" of laundry broadly means the steps involved in taking soiled laundry through washing, extraction and drying steps to render it in an acceptably clean state and may include preparation of the laundry for a liquid extraction operation, completion of the liquid extraction operation and further activity following the extraction operation. Reference to "laundry" in this specification primarily means linen in the form of undergarments, bed linen, table linen, etc., and other articles suitable for normal laundering but may also include other items such as cleaning cloths, skins or the like.
In a conventional laundry treating system wherein laundry is subjected to washing in a washing unit and then transported to a different unit for further treatment, the laundry is typically saturated with rinse water just prior to its discharge from the washing unit and is, therefore, subjected to pre-extraction to reduce the saturation before further liquid removal in a dryer unit and/or subsequent wringing. The preceding operation, which herein is referred to as "water extraction," may be carried out in spin-drying units which involve the application of centrifugal force, or may be accomplished by the use of mangles or wringers which utilize pressure for water extraction. Although a centrifuge involves a higher capital investment, it is acknowledged in the art as superior to wringers for water extraction purposes, extracting water not only more rapidly but to a significantly higher degree. For this reason it is generally found in a commercial laundry that laundering in a washing machine is usually followed by a treatment step in a spin-dryer and this is followed by transporting the laundry either to a dryer or to a wringer and may also involve the interposition of a tumbler to loosen the items in the laundry batch.
In most installations spin dryers are units with a vertical axis which are charged and emptied in various ways and the laundry is generally transported between different units of a laundry system or plant by means of conveyor belts or similar transporting means. A main problem of such systems is the charging of the spin-drying unit because wet clothing has characteristics or properties which resist the application of conventional conveying technology. A further problem of such systems is the uniform distribution of a batch of laundry in the spin-dryer unit. Non-uniform distribution results in load imbalance and the consequent disadvantages associated therewith, particularly bearing and shaft stress, noise of operation and a reduced useful life of the unit. Unloading of the spin-drying unit after the water extraction operation is an even greater problem. The laundry, which has been subjected to centrifugal force, tends to bind densely against the inside of the spin-drying drum and stick against the drum inside surface. The effect is further intensified because the preceding washing and transfer of the laundry to the spin-drying unit, and the subsequent application thereto of the spin-drying operation, tends to thoroughly mix, tangle and tightly compress the laundry when it is compacted outwardly by the centrifugal force. Consequently, even when manual release of the laundry from the spin-drying drum, after water extraction, is accomplished, the laundry is nevertheless so compressed that it requires tumbling in a separate unit to loosen the compressed mass into separate clothing items.
Still another common problem of known laundry systems is the considerable expenditure associated with the equipment and labor involved in accomplishing the transfer of laundry, after washing or water extraction, from one station to another, which frequently includes the additional disadvantage of laundry items being mislocated to dangle from conveyor belts or similar devices.